AppFog

AppFog began in 2010 as PHP Fog, the first platform-as-a-service aimed squarely at PHP, and broadened into a multi-language platform built on Cloud Foundry under the shorter name. It was one of the larger independent platforms of its moment, with a free tier that put a great many first applications online.

CenturyLink acquired it in June 2013 and put it in the Savvis cloud division, saying at the time that the deal ensured AppFog was not going anywhere. The first version was retired within two years, and the service shut down on 31 August 2016.

Three years from acquisition to shutdown is roughly the median in this group. It is also why the ownership field is recorded for every provider in the register: who owns a platform is the fact that most reliably predicts how long it stays the platform somebody bought.